Iron is produced by smelting raw iron ore material in a blast furnace. Molted iron collects at the bottom of the furnace and is periodically tapped out of the furnace through a tapping hole. As the furnace nears empty, the tapping hole is closed by a mudgun. The mudgun is advanced toward the taphole and a nozzle of the mudgun inserted into an accommodating taphole socket after which refractory clay material is injected into the taphole through an opening in a front endface of the nozzle. As the nozzle approaches the taphole socket, a lower portion of the nozzle and particularly the lower portion of the endface comes into direct contact with the molten metal and slag exiting the taphole. Over time, the repeated exposure to the molten iron and corrosive slag material erodes the nozzle tip and impairs the ability of the nozzle to properly seal the taphole socket allowing the molten iron, slag, and injected clay material to pass by the nozzle.
In the past, the nozzle was left unprotected and the exposed portion allowed to erode, requiring periodic replacement and repair of damaged nozzles. This practice, however, is costly and labor intensive as it requires a large number of nozzles to be kept on hand and trained personnel who are skilled in replacing nozzles and repairing damaged ones.
Recently, I developed a nozzle guard illustrated in FIG. 1 of the drawings which fits over the nose and endface of the nozzle shielding the otherwise exposed portion of the nozzle from contact with the outflowing molten metal and slag during taphole closure operations. This nozzle guard has an annular ring portion that fits over the endface of the nozzle serving as a face shield and a frusto-conical skirt portion extending around the entire outer perimeter of the ring portion and flaring rearwardly to cover the correspondingly shaped tapered nose of the nozzle protecting it from exposure to the molten metal. The top portion of the skirt has a pair of cutouts that receive a corresponding pair of hillside washers mounted on the nozzle upon sliding the nozzle guard over the nozzle to secure the guard to the nozzle. The ring portion and skirt are fabricated of combustible materials such as wood and pressboard materials and coated with a protective refractory material.
This nozzle guard adequately protects the otherwise exposed portions of the nozzle from erosion by the molten metal and slag. However, it also covers and provides unneeded protection to the top portions of the nozzle that normally are not exposed to the molten metal and slag. The unneeded upper portion of the guard may not completely burn during the taphole closing procedure interfering with the ability of the nozzle to properly seat and seal in the taphole socket. Modification of the nozzle to include the hillside washers is also necessary to secure the guard on the nozzle.